let str = `469 463 1481.53 10.5 1895 
930.21 9.9 24 1680 463 11 33 37 2158.13 200
1895 1610.55 463 10 1895 11.5`;

const arr = str.split('\n').map((s) => s.split(' ').map((n) => +n));
console.log(arr.map((list) => list.reduce((p, i) => p + i)).reduce((p, e) => e + p) / 3);
